Astronomy on Mars

Astronomy on Mars image

See also: Extraterrestrial sky: Mars Mosaic of two different Mars Global Surveyor Mars Orbiter Camera (MOC) exposures of Earth, the Moon, and Jupiter from 2003 Mars sky turned violet by water ice clouds Close-up of Mars sky at sunset, showing more color variation, as imaged by Mars Pathfinder

In many cases astronomical phenomena viewed from the planet Mars are the same or similar to those seen from Earth but sometimes (as with the view of Earth as an evening/morning star) they can be quite different. For example, because the atmosphere of Mars does not contain an ozone layer, it is also possible to make UV observations from the surface of Mars.

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Seasons

See also: Climate of Mars and Timekeeping on Mars

Mars has an axial tilt of 25.19°, quite close to the value of 23.44° for Earth, and thus Mars has seasons of spring, summer, autumn, winter as Earth does. As on Earth, the southern and northern hemispheres have summer and winter at opposing times.

However, the orbit of Mars has significantly greater eccentricity than that of Earth. Therefore, the seasons are of unequal length, much more so than on Earth:

In practical terms, this means that summers and winters have different lengths and intensities in the northern and southern hemispheres. Winters in the north are warm and short (because Mars is moving fast near its perihelion), while winters in the south are long and cold (Mars is moving slowly near aphelion). Similarly, summers in the north are long and cool, while summers in the south are short and hot. Therefore, extremes of temperature are considerably wider in the southern hemisphere than in the north.

Mars sky at noon, as imaged by Mars Pathfinder (June, 1999). ...read more
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